there has been a lot love&hate about the new Warband now, so I'm doing my best to help you improve your game a bit.

The modding-community is slowly starting to expand to Warband, and the "MBTweak"-tool, known from the first Mount and Blade, is already available for Warband!
There are some restrictions though, for example the quest-modifier does not work yet, but overall you can do quite a few things to vastly improve your Singleplayer-game!

For all the possible options & the download itself check this link:
http://www.mbrepository.com/file.php?id=1751

The good old Battlesize-Changer also works for Warband now:
http://www.mbrepository.com/file.php?id=1761

Be sure to check the MBRepository frequently for new stuff, I'm sure some of the more famous mods will find their way to Warband very soon.